BACKENDS: Compress screenshots using PNG if available

Closes gh-948.

1 files changed, 22 insertions, 18 deletions

diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index a595d076db..fc27270648 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -28,6 +28,7 @@
 #include "backends/graphics/opengl/pipelines/shader.h"
 #include "backends/graphics/opengl/shader.h"
 
+#include "common/array.h"
 #include "common/textconsole.h"
 #include "common/translation.h"
 #include "common/algorithm.h"
@@ -43,6 +44,10 @@
 #include "graphics/font.h"
 #endif
 
+#ifdef USE_PNG
+#include "image/png.h"
+#endif
+
 namespace OpenGL {
 
 OpenGLGraphicsManager::OpenGLGraphicsManager()
@@ -1311,33 +1316,35 @@ bool OpenGLGraphicsManager::saveScreenshot(const Common::String &filename) const
 	// Since we use a 3 byte per pixel mode, we can use width % 4 here, since
 	// it is equal to 4 - (width * 3) % 4. (4 - (width * Bpp) % 4, is the
 	// usual way of computing the padding bytes required).
+	// GL_PACK_ALIGNMENT is 4, so this line padding is required for PNG too
 	const uint linePaddingSize = width % 4;
 	const uint lineSize        = width * 3 + linePaddingSize;
 
-	// Allocate memory for screenshot
-	uint8 *pixels = new uint8[lineSize * height];
+	Common::DumpFile out;
+	if (!out.open(filename)) {
+		return false;
+	}
 
-	// Get pixel data from OpenGL buffer
-	GL_CALL(glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels));
+	Common::Array<uint8> pixels;
+	pixels.resize(lineSize * height);
+	GL_CALL(glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, &pixels.front()));
 
+#ifdef USE_PNG
+	const Graphics::PixelFormat format(3, 8, 8, 8, 0, 16, 8, 0, 0);
+	Graphics::Surface data;
+	data.init(width, height, lineSize, &pixels.front(), format);
+	return Image::writePNG(out, data, true);
+#else
 	// BMP stores as BGR. Since we can't assume that GL_BGR is supported we
 	// will swap the components from the RGB we read to BGR on our own.
 	for (uint y = height; y-- > 0;) {
-		uint8 *line = pixels + y * lineSize;
+		uint8 *line = &pixels.front() + y * lineSize;
 
 		for (uint x = width; x > 0; --x, line += 3) {
 			SWAP(line[0], line[2]);
 		}
 	}
 
-	// Open file
-	Common::DumpFile out;
-	if (!out.open(filename)) {
-		delete[] pixels;
-		return false;
-	}
-
-	// Write BMP header
 	out.writeByte('B');
 	out.writeByte('M');
 	out.writeUint32LE(height * lineSize + 54);
@@ -1354,13 +1361,10 @@ bool OpenGLGraphicsManager::saveScreenshot(const Common::String &filename) const
 	out.writeUint32LE(0);
 	out.writeUint32LE(0);
 	out.writeUint32LE(0);
+	out.write(&pixels.front(), pixels.size());
 
-	// Write pixel data to BMP
-	out.write(pixels, lineSize * height);
-
-	// Free allocated memory
-	delete[] pixels;
 	return true;
+#endif
 }
 
 } // End of namespace OpenGL